It is frequently desirable to remotely actuate or trigger the blocking and unblocking of an orifice, or vice versa, for any of a large number of purposes. For example, it may be desirable to allow, for a certain period of time, a fluid from one region to pass into another, e.g. in the case of an activation fluid such as a battery electrolyte and an activation system such as a primary battery.
In another case, for instance, it is desirable to unblock an air intake orifice for the collection of air samples by a cryocollector, e.g. as described in the concurrently filed copending application entitled "Cryogenic Pump and Air Sample".
The term "remote actuation" is used herein to refer to the operation of the closure for the orifice from any distance, e.g. through signals transmitted by any electromagnetic radiation system, e.g. radiowaves, microwaves or laser, between a transmitting station and the remote location of the opening which is to be selectively blocked and unblocked. This opening can be located in a satellite orbiting the earth or in a ship travelling through space, or in a balloon-supported instrument, etc. Naturally, the signal transmission may be effected by other means as well. It also refers to altitude-triggered operations using an altimeter on a vehicle, etc.
In all remote operation systems, the principal desire is for reliability, especially since the remote location is generally inaccessible for maintenance operations. The device should, therefore, remain activatable over long periods and even after long periods of standing, should be capable of being actuated with a given response.
In prior-art systems for selectively blocking and unblocking openings or orifices, motor-driven members have been employed. Such systems are expensive and heavy, while being of only limited reliability. In fact, motor-driven valves for closures require comparatively frequent maintenance and inspection.